High performance submicron-gate SiGe p-type modulation-doped field-effect transistors

High transconductance p-type field-effect transistors (FETs) are essential for the fabrication of high speed complementary circuits. Unfortunately, the much lower mobility of holes in comparison to electrons in Si has been responsible for the large gap between the performance of n-type and p-type devices. Recent advances in the growth of high quality SiGe has lead to structures with higher hole mobilities. This has been attributed to the light hole-heavy hole band splitting which results in less band mixing and a smaller in-plane effective mass. In this work, we report our work on the fabrication and characterization of p-type modulation-doped field effect transistors (MODFETs) in high mobility SiGe heterostructures. High transconductance and unity current-gain cut-off frequency are demonstrated for submicron-gate MODFETs.